There may be fractional reserve money and there is no reason to worry. The difference, when it exists, between real money and fractional reserve money will be clear, because either you have bitcoins in an andress that only you have access or you don't. Bitcoin notes or digits in some bitcoin bank account will not be bitcoin and everyone with basic knowledge will be able do deduce this. The problem today is exactly the fact that this distinction between "real money" and "fractional reserve generated money" is not clear because there is no such thing as a the bitcoin protocol, adresses, private keys, etc for fiat money and because there are central banks to act as lender of last resort, which does not exist in bitcoin.